The present invention relates to a method and a device for resetting the position of pins in trays with pins for supporting objects, particularly objects such as panels for producing furniture components or the like, to be clad inside presses.
As is known, the cladding of panels, particularly panels for manufacturing furniture components, by means of a thin sheet made of synthetic material, veneering or the like, is generally performed by heating the cladding sheet and making it adhere to the panel inside a press.
In many cases, the thin sheet must clad one of the larger faces of the panel and the lateral faces that are adjacent to such larger face.
Due to this requirement, the panels to be clad are generally fed to the press by depositing them on a tray that supports the panel by virtue of a plurality of pins. More particularly, the panel is rested on the tray on a substantially horizontal plane and is supported by multiple pins that have a substantially vertical axis and make contact with the lower face of the panel, which is one of the two larger faces of the panel and lies opposite the face that is meant to be clad together with the lateral faces.
In order to allow the cladding sheet to cover the lateral faces completely, generally the pins of the tray can be arranged in two positions: a raised position, in which they make contact with the lower face of the panel, and a lowered position, in which they are spaced below the lower face of the panel, which is supported by the pins that are instead in the raised position. The pins that are fully covered by the panel are moved to the raised position, manually or mechanically or kept in the raised position before or after depositing the panel on the tray, while the pins that are meant to be covered only partially or not covered by the panel are moved to the lowered position or kept thereat. In this manner, the panel rests on the pins in the raised position with its lower face, except for a region that is proximate to the edge of the panel, so that the thin sheet, as a consequence of the pressure applied by the press, optionally with the aid of suction applied to the lower face of the thin sheet, can adhere to the upper face and to the lateral faces of the panel.
A tray of this kind is disclosed EPA 01111247.1, by the same Applicant, which is assumed included herein as reference.
The tray disclosed in the above patent application is arranged on a substantially horizontal plane and is used to insert and extract the panels to be clad in the press. More particularly, the tray has multiple receptacles that have a substantially vertical axis; each receptacle accommodates a pin that is provided with a head that protrudes from the upper face of the tray. All together, the pins form, by way of their heads, a supporting surface for the lower face of the panel to be clad. The pins can move individually on command, along the axis of the corresponding receptacle, in order to pass from the raised position, in which they are suitable to make contact with the panel and support it, to a lowered position, in which they are spaced below the panel. For each pin there are elastic means that cooperate with the pin and the corresponding receptacle so as to retain the pin in the raised position. The elastic means are flexible in order to allow the corresponding pin to pass from the raised position to the lowered position or vice versa.
When it is necessary to pass from the cladding of one type of panel to another type of panel that is different in terms of dimensions and/or shape, it is necessary to perform a so-called xe2x80x9cresetxe2x80x9d of the position of the pins in the previously used tray. The resetting operation substantially consists in moving all the pins to the lower position or to the raised position, so as to be then able to move into the raised position, or keep thereat, only the pins whose head is meant to be covered completely by the new panel to be clad.
In the patent application cited above, among the various possibilities for resetting the position of the pins that are considered, a resetting is described which is performed by lifting the pins that had been lowered during the preceding process. The same patent application considers the possibility of performing this operation by lowering the tray onto a substantially horizontal abutment surface that is arranged in a downward region and can also be constituted by the lower platen of the press, so that during this downward motion the lower end of the pins rests against the surface and accordingly all the pins that are in the lowered position are moved to the raised position.
The transfer of the pins from the lowered position to the raised position is contrasted, particularly in the final portion of the upward movement, by the elastic means provided for each pin, which are meant to subsequently keep the pin in the raised position.
Owing to the large number of pins that are usually present in trays of this kind, the sum of the elastic reactions of the elastic means for each pin can be so large as to cause an upward deformation of the tray.
Currently, in order to avoid the deformation of the tray, during the resetting of the position of the pins an appropriately provided panel is arranged above the tray; such panel is provided with blades that by fitting between the pins contrast the lifting of the part of the tray in which the receptacles for the pins are formed. However, this remedy has the drawback that it increases the time required to reset the position of the pins, since it requires to load the panel with the blades onto the tray and then unload it.
Actually, there are other resetting systems that are based on an individual or grouped action on the pins, but these systems are generally complicated, since they use actuators of the mechanical or pneumatic type that have considerable costs and are complicated to actuate.
The aim of the present invention is to solve the above described problem, by providing a method and a device for resetting the position of pins in trays with pins for supporting objects, particularly objects such as panels for producing furniture components or the like, to be clad inside presses, that allows to reset the position of the pins very simply and rapidly, avoiding deformations of the tray.
Within this aim, an object of the invention is to provide a method and a device that allow to reset the position of the pins without requiring the use of auxiliary devices to contrast the deformation of the tray.
Another object of the invention is to provide a device for resetting the position of the pins that does not complicate substantially the press and the devices for moving the tray.
This aim and these and other objects that will become better apparent hereinafter are achieved by a method for resetting the position of pins in trays with pins for supporting objects, particularly objects such as panels for producing furniture components or the like, to be clad inside presses, of the type that comprises a tray that is arranged on a substantially horizontal plane and in which there are multiple receptacles that have a substantially vertical axis, each receptacle accommodating a pin provided with a head that protrudes from the upper face of said tray; said pins forming all together, with their heads, a supporting surface for the lower face of an object to be placed in the press; said pins being individually movable on command along the axis of the corresponding receptacle in order to pass from a raised position, in which they are suitable to make contact with said object and support it, to a lowered position, in which they are spaced downward from the object supported by the pins in the raised position, each pin having elastic means that are suitable to keep the pin in the raised position and are flexible so as to allow the pin to pass from the raised position to the lowered position or vice versa, characterized in that it comprises the step of making said tray slide along a resetting surface that has, along its extension, a region that is raised with respect to a plane that is parallel to the plane of arrangement of said tray, said raised region being suitable to gradually make contact with the lower end of the pins in the lowered position, as they pass at said raised region, in order to produce their transfer to the raised position.